EU-1 zeolite catalyst and a process for the reduction of the pour point of feeds containing paraffins

ABSTRACT

The invention concerns a process for improving the pour point of a feed comprising paraffins containing more than 10 carbon atoms, in which process the feed to be treated is brought into contact with a catalyst comprising an EU-1 zeolite and at least one hydro-dehydrogenating element, at a temperature which is in the range 170° C. to 500° C., a pressure in the range 1 to 250 bar and an hourly space velocity in the range 0.05 to 100 h −1 , in the presence of hydrogen in a proportion of 50 to 2000 l/l of feed. The oils obtained have good pour points and high viscosity indices (VI). The process is also applicable to gas oils and other feeds requiring a reduction of pour point. The invention also concerns an EU-1 zeolite from which a portion of elements T (Al, Ga, Fe or B) have been removed and which has an Si/T atomic ratio of at least 10.

The present invention concerns a process for improving the pour point offeeds containing linear and/or slightly branched, long (more than 10carbon atoms) paraffins, to provide good yields on converting feeds withhigh pour points to at least one cut with a low pour point and a highviscosity index for oil bases.

The present invention also concerns a EU-1 zeolite from which a portionof the elements Al, Fe, Ga or B has been removed, for exampledealuminated, a catalyst containing that zeolite, its use in convertinghydrocarbons, and a process for reducing the pour point using thatcatalyst.

BACKGROUND OF THE INVENTION

High quality lubricants are fundamentally important for the properoperation of modern machines, automobiles and trucks. However, thequantity of paraffins originating directly from untreated crude oil withproperties which are suitable for use in good lubricants is very lowwith respect to the increasing demand in this sector.

Heavy oil fractions containing large amounts of linear or slightlybranched paraffins must be treated in order to obtain good quality oilbases in the best possible yields, using an operation which aims toeliminate the linear or slightly branched paraffins from feeds which arethen used as base stock, or as kerosene or jet fuel.

High molecular weight paraffins which are linear or very slightlybranched which are present in the oils or kerosene or jet fuel result inhigh pour points and thus in coagulation for low temperatureapplications. In order to reduce the pour points, such linear paraffinswhich are not or are only slightly branched must be completely orpartially eliminated.

This operation can be carried out by extracting with solvents such aspropane or methyl ethyl ketone, termed dewaxing, with propane or methylethyl ketone (MEK). However, such techniques are expensive, lengthy andnot always easy to carry out.

A further technique is selective cracking of the longest linear paraffinchains to form compounds with a lower molecular weight, part of whichcan be eliminated by distillation.

Because of their form selectivity, zeolites are among the most widelyused catalysts. The idea underlying their use is that zeoliticstructures exist which have pore openings which allow long linear orvery slightly branched paraffins to enter their micropores but whichexclude branched paraffins, naphthenes and aromatic compounds. Thisphenomenon leads to selective cracking of linear or very slightlybranched paraffins.

Zeolite based catalysts with intermediate pore sizes such as ZSM-5,ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35 and ZSM-38 have been describedfor their use in such processes.

Processes using such zeolites can produce oils by cracking feedscontaining less than 50% by weight of linear or linear or very slightlybranched paraffins. However, for feeds containing higher quantities ofthese compounds, it has become apparent that cracking them leads to theformation of large quantities of products with lower molecular weightssuch as butane, propane, ethane and methane, which considerably reducesthe yield of desired products.

In order to overcome these disadvantages, we have concentrated ourresearch on developing catalysts which also encourage isomerisation ofsuch compounds.

SUMMARY OF THE INVENTION

The invention provides a process for improving the pour point of aparaffinic feed comprising paraffins containing more than 10 carbonatoms, in which process the feed to be treated is brought into contactwith a catalyst based on EU-1 zeolite and at least onehydro-dehydrogenating element, at a temperature which is in the range170° C. to 500° C., a pressure in the range 1 to 250 bar and an hourlyspace velocity in the range 0.05 to 100 h⁻¹, in the presence of hydrogenin a proportion of 50 to 2000 l/l of feed.

EU-1 zeolite in its hydrogen form, termed H-EU-1, obtained by calciningand/or ion exchanging as synthesized EU-1, used in the process of theinvention, and its synthesis are described in European patent EP-B1 0042 226. That zeolite has the following molar composition: 0.5 to 1.5R₂O: T₂O₃: at least 10 XO₂: 0 to 100 H₂O, where R is a monovalent cationor 1/n of a cation with valency n, X is silicon and/or germanium, T isAl, Fe, Ga or B and the water is water of hydration which adds to theinitial water present when R is H. This EU-1 zeolite is characterized bythe following X ray diffraction table:

X ray diffraction table for zeolite in the form Na—H—EU-1, i.e.,partially in its hydrogen form and containing sodium.

Dhkl (Å) I/I₀ 11.11 ± 0.15  vs 10.03 ± 0.15  vs 9.78 ± 0.15 w 7.62 ±0.15 w 6.84 ± 0.10 m 6.21 ± 0.10 vw 5.73 ± 0.10 w 4.87 ± 0.08 vw 4.60 ±0.08 vs 4.30 ± 0.08 vs 3.97 ± 0.06 vs 3.77 ± 0.06 s 3.71 ± 0.04 w 3.63 ±0.04 vw 3.42 ± 0.04 m 3.33 ± 0.04 m 3.27 ± 0.04 s 3.23 ± 0.04 m 3.15 ±0.04 w 3.07 ± 0.04 w 2.93 ± 0.04 w 2.69 ± 0.04 w 2.63 ± 0.04 vw 2.57 ±0.04 vw 2.51 ± 0.03 w 2.45 ± 0.03 vw 2.41 ± 0.03 vw 2.32 ± 0.02 vw 2.29± 0.02 vw 2.11 ± 0.02 vw I/I₀ represents the relative intensities ofpeaks graduated on the following scale: w = weak (I/I₀ in the range 0 to20); m = medium (I/I₀ in the range 20 to 40); s = strong (I/I₀ in therange 40 to 60); vs = very strong (I/I₀ in the range 60 to 100).

EU-1 zeolite with structure type EUO, used in the present invention hasa one-dimensional microporous network with pore openings delimited by 10T atoms (tetrahedral atoms: Si, Al, Ga, Fe . . . ), with a pore diameterof 4.1×5.7 Å. This structure is described in “The Atlas of ZeoliteStructure Types”, by W. M. Meier, D. H. Olson and Ch. Baerlocher, FourthEdition, 1996. This zeolite also has wide lateral pockets along itsprincipal channels with pore openings delimited by 10 T atoms(tetrahedral atoms: Si, Al, Oa, Fe . . . ) with dimensions of about6.8×5.8 Å.

The term “pore opening of 10 or 12 tetrahedral atoms (T)” means poresconstituted by 10 or 12 sides.

The process can advantageously convert a feed with a high pour point toa mixture (for example oil) with a lower pour point and, in the case ofoil, a high viscosity index. It can also be applied to reducing the pourpoint of gas oils, for example.

Among others, the feed is composed of linear and/or slightly branchedparaffins containing at least 10 carbon atoms, preferably 15 to 50carbon atoms, and advantageously 15 to 40 carbon atoms. Heavy feedscontain paraffins essentially containing more than 30 carbon atoms andproduce base stock; gas oils are lighter and contain paraffinscontaining 10-30 carbon atoms.

The isomerised products may contain about 65% to 80% of single-branchedproducts and about 20% to 35% of multi-branched products. The term“single-branched products” means linear paraffins comprising a singlemethyl group, and the term “two-branched products” means linearparaffins containing 2 methyl groups which are not carried by the samecarbon atom. Thus “multi-branched” paraffins can be defined byextension.

Further, the catalyst comprises at least one hydro-dehydrogenatingfunction, for example a group VIII metal (noble or non-noble) or acombination of at least one group VIII (non noble) metal or compound andat least one group VI metal or compound, and the reaction is carried outunder conditions which will be described below.

Using the EU-1 zeolite of the invention under the conditions describedabove can produce products with a low pour point and oils with a highviscosity index, in good yields.

DETAILED DESCRIPTION OF THE INVENTION

EU-1 zeolite has an Si/T atomic ratio in the range 5 to 600 and inparticular in the range 10 to 300.

The global Si/T ratio of the zeolite and the chemical composition of thesamples are determined by X ray fluorescence and atomic absorption.

The EU-1 zeolite used in the process of the invention can be obtainedwith the desired Si/T ratio for the catalytic application of theinvention directly by synthesis by adjusting the operating conditionsfor synthesis. Then the zeolite is calcined and exchanged by at leastone treatment using a solution of at least one ammonium salt to obtainthe ammonium form of the zeolite which, once calcined, leads to thehydrogen form of the zeolite.

Advantageously, in other cases the EU-1 zeolite has undergone atreatment aimed at eliminating (removing) a portion of elements T, forexample aluminium (in which case it is dealumination) so as to increasethe low Si/T ratio obtained on synthesis.

This zeolite is obtained from as synthesised zeolite and thus containssilicon and an element T selected from the group formed by Al, Fe, Gaand B. A portion of elements T have been removed from the zeoliteframework and advantageously they are extracted from the sample (theythen pass into solution in the case of acid attack).

Thus the global Si/T atomic ratio of the zeolite is greater than that ofthe starting zeolite, the difference (increase) is at least equal to 10%of the Si/T ratio of the starting zeolite.

The surface Si/T atomic ratio (obtained by XPS) does not diminish, andgenerally it increases by a substantial amount.

The global Si/T atomic ratio is at least 10, preferably at least 20, ormore preferably over 60, and generally EU-1 zeolites are used with Si/Alratios of at most 600, preferably at most 300. Si/T ratios of 20 to 200or even 20 to 100 are particularly advantageous.

The zeolite constitutes a further aspect of the invention.

The dealuminated EU-1 zeolite of the invention, in the preferred casewhere T is Al, can be prepared using two dealumination methods from assynthesised EU-1 zeolite containing an organic structuring agent. Thesemethods are described below. However, any other method which is known tothe skilled person can also be used. These methods described foraluminium (Al) can also be used for other elements T.

The first (preferred) method, direct acid attack, comprises a firstcalcining step carried out in dry air, at a temperature which isgenerally in the range 450° C. to 550° C., which eliminates the organicstructuring agent present in the micropores of the zeolite, followed bya step in which the zeolite is treated with an aqueous solution of amineral acid such as HNO₃ or HCl or an organic acid such as CH₃CO₂H.This latter step can be repeated as many times as is necessary to obtainthe desired degree of dealumination. Between these two steps, one ormore ion exchange steps can be carried out using at least one NH₄NO₃solution, to at least partially and preferably almost completelyeliminate the alkaline cation, in particular sodium. Similarly, at theend of the direct acid attack dealumination step, one or more ionexchange steps may be carried out using at least one NH₄NO₃ solution toeliminate residual alkaline cations, in particular sodium.

In order to obtain the desired Si/Al ratio, the operating conditionsmust be correctly selected; the most critical parameters in this respectare the temperature of the treatment with the aqueous acid solution, theconcentration of the latter, its nature, the ratio between the quantityof acid solution and the mass of the treated zeolite, the treatmentperiod and the number of treatments carried out.

Dealumination can also be achieved using chemical dealuminating agentssuch as (by way of non exhausting examples) silicon tetrachloride(SiCl₄), ammonium hexafluorosilicate [(NH₄)₂SiF₆], andethylenediaminetetra-acetic acid (EDTA), including its mono and disodiumforms. These reactants can be used in solution or in the gaseous phase,for example in the case of SiCl₄.

The second method, heat treatment (in particular using steam, bysteaming)+acid attack, comprises firstly calcining in dry air at atemperature which is generally in the range 450° C. to 550° C., toeliminate the organic structuring agent occluded in the micropores ofthe zeolite. The solid obtained then undergoes one or more ion exchangesusing at least one NH₄NO₃ solution, to eliminate at least a portion,preferably practically all, of the alkaline cation, in particularsodium, present in the cationic position of the zeolite. The zeoliteobtained then undergoes at least one framework dealumination cyclecomprising at least one heat treatment which is optionally andpreferably carried out in the presence of steam, at a temperature whichis generally in the range 500° C. to 900° C., and followed by at leastone acid attack using an aqueous solution of a mineral or organic acidas defined above. The conditions for calcining in the presence of steam(temperature, steam pressure and treatment period), also thepost-calcining acid attack conditions (attack period, concentration ofacid, nature of acid used and the ratio between the volume of the acidand the mass of zeolite) are adapted so as to obtain the desired levelof dealumination. For the same reason, the number of heat treatment-acidattack cycles can be varied.

In a variation of this second method, the acid attack step, i.e.,treatment using a solution of an acid, can be replaced by treatment witha solution of a chemical dealuminating compound such as those citedabove, for example, namely silicon tetrachloride (SiCl₄), ammoniumhexafluorosilicate [(NH)₂SiF₆], ethylenediaminetetra-acetic acid (EDTA),including its mono and disodium forms.

In the preferred case when T is Al, the framework dealumination cycle,comprising at least one heat treatment step, optionally and preferablycarried out in the presence of steam, and at least one attack stepcarried out in an acid medium on the EU-1 zeolite, can be repeated asoften as is necessary to obtain the dealuminated EU-1 zeolite having thedesired characteristics. Similarly, following the heat treatment,optionally and preferably carried out in the presence of steam, a numberof successive acid attacks can be carried out using different acidconcentrations.

In a variation of this second calcining method, heat treatment of theEU-1 zeolite containing the organic structuring agent can be carried outat a temperature which is generally in the range 500° C. to 850° C.,optionally and preferably in the presence of steam. In this case, thesteps of calcining the organic structuring agent and dealuminating theframework are carried out simultaneously. The zeolite is then optionallytreated with at least one aqueous solution of a mineral acid (forexample HNO₃ or HCl) or an organic acid (for example CH₃CO₂H). Finally,the solid obtained can optionally undergo at least one ion exchange stepusing at least one NH₄NO₃ solution, to eliminate practically all of thealkaline cations, in particular sodium, present in the cationic positionin the zeolite.

The modified EU-1 zeolite (and advantageously that in which the globalto Si/T ratio is at least 20 or over 20) of the invention is at leastpartially, preferably practically completely, in its acid form, i.e., inits hydrogen (H⁺) form. The Na/T atomic ratio is generally less than10%, preferably less than 5%, and more preferably less than 1%.Preferably, the modified EU-1 has a global Si/T ratio of 20 to 200,preferably 20 to 100.

The catalyst of the invention contains EU-1 zeolite with an Si/T ratioof at least 10, which may or may not be mixed with a matrix, andoptionally at least one hydro-dehydrogenating element, which is a noblemetal or a combination of at least one group VI metal or compound and atleast one group VIII metal or compound.

The catalyst used in the process of the invention contains at least onehydro-dehydrogenating element, for example at least one group VIIImetal. It may be a noble metal, advantageously selected from the groupformed by Pt or Pd, which is introduced into the molecular sieve by dryimpregnation or ion exchange, for example, or by any other method whichis known to the skilled person, or it is introduced into the matrix.

The amount of metal thus introduced, expressed as the weight % withrespect to the mass of molecular sieve engaged, is generally less than5%, preferably less than 3%, and the amount of noble metal in thecatalyst is generally less than 2% by weight.

The hydro-dehydrogenating element can also be a combination of at leastone group VI metal or compound (for example molybdenum or tungsten) andat least one group VIII metal or compound (for example nickel orcobalt). The total concentration of group VI and group VIII metals,expressed as the metal oxides with respect to the support, is generallyin the range 5% to 40% by weight, preferably in the range 7% to 30% byweight. The weight ratio (expressed as the metallic oxides) of groupVIII metals to group VI metals is preferably in the range 0.05 to 0.8:more preferably in the range 0.13 to 0.5.

The element can also be rhenium and/or niobium, used alone or incombination with the group VIII and/or VI elements.

This type of catalyst can advantageously contain phosphorous, thecontent of which is generally less than 15% by weight, preferably lessthan 10% by weight, expressed as phosphorous oxide P₂O₅ with respect tothe support.

When treating a real feed, the molecular sieve of the invention is firstformed. In a first variation, the molecular sieve can have at least onegroup VIII metal, radical selected from the group formed by platinum andpalladium, deposited on it, and it can be formed by any technique whichis known to the skilled person. In particular, it can be mixed with amatrix, which is generally amorphous, for example a moist alumina gelpowder. The mixture is then formed, for example by extrusion through adie. The amount of molecular sieve in the mixture obtained is generallyin the range 0.5% to 99.9%, advantageously in the range 5% to 90% byweight, with respect to the mixture (molecular sieve+matrix) andpreferably in the range 10% to 90%, more preferably in the range 20% to70%.

In the remaining text, the term “support” is used to describe themolecular sieve+matrix mixture.

Forming can be carried out with matrices other than alumina, such asmagnesia, amorphous silica-aluminas, natural clays (kaolin, bentonite,sepiolite, attapulgite), silica, titanium oxide, boron oxide, zirconia,aluminium phosphates, titanium phosphates, zirconium phosphates, andmixtures thereof. Techniques other than extrusion, such as pelletizationor bowl granulation, can be used.

The group VIII hydrogenating metal, preferably Pt and/or Pd, can alsovery advantageously be deposited on the support using any process whichis known to the skilled person which can deposit metal on the molecularsieve. Competitive cation exchange can be used, with ammonium nitrate asthe preferred competing agent, the competition ratio being at leastabout 20 and advantageously about 30 to 200. When platinum or palladiumis used, a platinum tetramine complex or a palladium tetramine complexis normally used: these latter are almost completely deposited on themolecular sieve. This cation exchange technique can also be used todeposit the metal directly on powdered molecular sieve before mixing itwith any matrix.

Deposition of the group VIII metal(s) is generally followed by calciningin air or oxygen, usually between 300° C. and 600° C. for 0.5 to 10hours, preferably between 350° C. and 550° C. for 1 to 4 hours.Reduction in hydrogen can then follow, generally at a temperature whichis in the range 300° C. to 600° C. for 1 to 10 hours, preferably in therange 350° C. to 550° C. for 2 to 5 hours.

The platinum and/or palladium can also be deposited not directly on themolecular sieve, but on the matrix (alumina binder) before or afterforming, by anion exchange with hexachloroplatinic acid,hexachloropalladic acid and/or palladium chloride in the presence of acompeting agent, for example hydrochloric acid. As before, afterdepositing the platinum and/or palladium, the catalyst is generallycalcined then reduced in hydrogen as indicated above.

The non noble group VIII metals or an association of oxides of non noblegroup VI and VIII metals, comprising the hydro-dehydrogenating function,can be introduced into the catalyst at various stages of the preparationand in various fashions.

It can be introduced only in part (for associations of group VI and VIIImetal oxides) or completely on mixing the molecular sieve of theinvention with the gel of the oxide selected as the matrix. It can beintroduced using one or more ion exchange operations on the calcinedsupport constituted by the molecular sieve of the invention dispersed inthe selected matrix, using solutions containing precursor salts of theselected metals when these belong to group VIII. They may be introducedby one or more impregnation operations carried out on the formed andcalcined support, using a solution of precursors of oxides of metalsfrom group VIII (in particular cobalt or nickel) when the precursors ofoxides of metals from group VI (in particular molybdenum or tungsten)have been introduced first on mixing the support. Finally, it can beintroduced by one or more impregnation operations carried out on thecalcined support constituted by a molecular sieve of the invention andthe matrix, using solutions containing the precursor of the oxides ofmetals from groups VI and/or VIII, the precursors of oxides from groupVIII metals preferably being introduced after those of group VI or atthe same time as the latter. Impregnation methods lead to a deposit ofgroup VIII metal essentially on the binder.

When the metal oxides are introduced in a plurality of impregnationsteps using the corresponding precursor salts, an intermediate calciningstep must be carried out at a temperature in the range 250° C. to 600°C.

Molybdenum impregnation can be facilitated by adding phosphoric acid tothe ammonium paramolybdate solutions.

The mixture is then formed, for example by extrusion through a die. Theamount of molecular sieve in the mixture obtained is generally in therange 0.5% to 99.9%, advantageously in the range 10% to 90% by weightwith respect to the mixture (molecular sieve+matrix), preferably in therange 20% to 70%.

Deposit of the final metal is generally followed by calcining in air orin oxygen, usually between 300° C. and 600° C. for 0.5 to 10 hours,preferably between 350° C. and 550° C. for 1 to 4 hours.

It is then generally followed by sulphuration of the catalyst beforebringing it into contact with the feed, using any method known to theskilled person. Thus in this case the catalyst advantageously containssulphur.

The catalyst of the invention is used to convert hydrocarbons, inparticular to reduce the pour point as will be defined below.

The process for reducing the pour point as defined below can also becarried out using a catalyst containing a EU-1 zeolite, obtained bysynthesis, with the formula described above, in particular with a Si/Tratio of 5 to 600, advantageously 10 to 300. Zeolites with Si/T ratiosof less than 10 are thus included.

Feeds which can be treated using the process of the invention areadvantageously fractions with relatively high pour points the values ofwhich are to be reduced.

EXAMPLES

The process of the invention can be used to treat a variety of feeds,from relatively light fractions such as kerosenes and jet fuels to feedswith higher boiling points such as middle distillates, vacuum residues,gas oils, middle distillates from FCC (LCO and HCO) and hydrocrackingresidues.

The feed to be treated is, for the most part, a C₁₀ ⁺ cut with aninitial boiling point of more than about 175° C., preferably a heavy cutwith a boiling point of at least 280° C., advantageously a boiling pointof at least 380° C. The process of the invention is particularlysuitable for treating paraffinic distillates such as middle distillateswhich encompass gas oils, kerosenes, jet fuels, vacuum distillates andall other fractions with a pour point and viscosity which must beadapted to satisfy specifications.

Feeds which can be treated using the process of the invention cancontain paraffins, olefins, naphthenes, aromatics and heterocycles andhave a high proportion of high molecular weight n-paraffins and veryslightly branched paraffins, also of high molecular weight.

The reaction is carried out so that the cracking reactions remainsufficiently low to render the process economically viable. The amountof cracking reactions is generally below 40% by weight, preferably below30%, and advantageously below 20%.

Typical feeds which can advantageously be treated by the process of theinvention generally have a pour point of more than 0° C. The productsresulting from treatment in accordance with the process have pour pointsof below 0° C., preferably below about −10° C.

These feeds contain amounts of n-paraffins and very slightly branchedparaffins containing more than 10 carbon atoms, also with high molecularweight, of over 30% and up to about 90%, and in some cases more than 90%by weight. The process is of particular interest when this proportion isat least 60% by weight.

Non limiting examples of other foods which can be treated in accordancewith the invention are bases for lubricating oils, synthesised paraffinsfrom the Fischer-Tropsch process, high pour point polyalphaolefins,synthesised oils, etc . . . . The process can also be applied to othercompounds cottaining an n-alkane chain such as those defined above, forexample n-alkylcycloalkanes, or containing at least one aromatic group.

The process is carried out under the following operating conditions:

the reaction temperature is in the range 170° C. to 500° C., preferablyin the range 180° C. to 470° C., advantageously 190° C. to 450° C.;

the pressure is in the range 1 to 250 bar, preferably in the range 10 to200 bar;

the hourly space velocity (HSV expressed as the volume of feed injectedper unit volume of catalyst per hour) is in the range about 0.05 toabout 100, preferably about 0.1 to about 30 h⁻¹.

The feed and the catalyst are brought into contact in the presence ofhydrogen. The amount of hydrogen used, expressed in liters of hydrogenper liter of feed, is in the range 50 to about 2000 liters of hydrogenper liter of feed, preferably in the range 100 to 1500 liters ofhydrogen per liter of feed.

The quantity of nitrogen compounds in the feed to be treated ispreferably less than about 200 ppm by weight, more preferably less than100 ppm by weight. The sulphur content is below 1000 ppm by weight,preferably less than 500 ppm, more preferbly less than 200 ppm byweight. The quantity of metals in the feed, such as Ni or V, isextremely low, i.e., less than 50 ppm by weight, preferably less than 10ppm by weight and more preferably less than 2 ppm by weight.

The compounds obtained using the process of the invention may besingle-branched, two-branched and multi-branched compounds,advantageously with methyl groups.

The following examples illustrate the invention without limiting itsscope.

Example 1 Preparation of Catalyst C1 in Accordance with the Invention

The starting material was an EU-1 zeolite prepared in accordance withExample 4 of EP-B1-0 042 226, with a global Si/Al atomic ratio of 17.5,and a Na/Al atomic ratio of 0.8.

This EU-1 zeolite first underwent dry calcining at 550° C. in a streamof dry air for 18 hours. The solid obtained underwent four ion exchangesteps in a solution of 10 N NH₄NO₃ at about 100° C. for 4 hours for eachexchange step. The solid obtained was designated as NH₄-EU-1/1 and hadan Si/Al ratio of 18.1 and an Na/Al ratio of 0.003. The remainingphysico-chemical characteristics are shown in Table 1.

TABLE 1 Adsorption S_(BET) V(P/P₀ = 0.19) Sample (m²/g) ml liquid N₂/gNH₄-EU-1/1 434 0.18

The EU-1 crystallites were in the form of crystals 0.6 μm to 3 μm insize.

The NH₄-EU-1/1 zeolite was mixed with SB3 type alumina from Condéa. Themixed paste was extruded through a 1.4 mm die. The extrudates were thencalcined at 500° C. for 2 hours in air then dry impregnated with asolution of platinum tetramine chloride [Pt(NH₃)₄]Cl₂, and finallycalcined in air at 550° C. The platinum content in the final catalyst C1was 0.7% by weight and the zeolite content, expressed with respect tothe ensemble of the catalyst mass, was 30% by weight.

Example 2 Preparation of Catalyst C2 in Accordance with the Invention

The starting material was a EU-1 zeolite prepared in accordance withExample 4 of EP-A2-0 042 226 with a global Si/Al atomic ratio of 38.4,and contained sodium.

This EU-1 zeolite first underwent dry calcining at 550° C. in a streamof dry air for 18 hours. The solid obtained underwent four ion exchangesteps in a solution of 10 N NH₄NO₃ at about 100° C. for 4 hours for eachexchange step. The solid obtained was designated as NH₄-EU-1/1 and hadin Si/Al ratio of 39.6 and an Nm/Al ratio of 0.002. The remainingphysico-chemical characteristics as shown in Table 2.

TABLE 2 Adsorption S_(BET) V(P/P₀ = 0.19) Sample (m²/g) ml liquid N₂/gNH4-EU-1/2 427 0.18

The NH₄-EU-1/2 obtained then underwent ion exchange using a solution ofplatinum tetramine chloride [Pt(NH₃)₄]Cl₂ using the following protocol.The NH₄-EU-1/2 was suspended in an ammonium nitrate solution such thatthe molar ratio R=[NH₄ ⁺]/2*[Pt(NH₃)₄]Cl₂ was 25. The quantity of[Pt(NH₃)₄]Cl₂ complex introduced was such that the metallic platinumcontent (Pt) on the dry zeolite was 0.8%.

The Pt/NH₄-EU-1/2 zeolite prepared was mixed with SB3 type alumina fromCondéa. The mixed paste was extruded through a 1.4 mm die. Theextrudates were then calcined at 550° C. for 4 hours in air. Theplatinum content in the final catalyst C2 was 0.16% by weight and thezeolite content, expressed with respect to the ensemble of the catalystmass, was 50% by weight.

Example 3 Preparation of Catalyst C3 in Accordance with the Invention

The starting material was a EU-1 zeolite prepared in accordance withExample 5 of EP-B1-0 042 226, with a global Si/Al atomic ratio of 60,containing sodium.

This EU-1 zeolite first underwent dry calcining at 550° C. in a streamof dry air for 18 hours. The solid obtained underwent four ion exchangesteps in a solution of 10 N NH₄NO₃ at about 100° C. for 4 hours for eachexchange step. The solid obtained was designated as NH₄-EU-1/3 and hadan Si/Al ratio of 63 and an Na/Al ratio of 0.002. The remainingphysico-chemical characteristics are shown in Table 3.

TABLE 3 Adsorption S_(BET) V(P/P₀ = 0.19) Sample (m²/g) ml liquid N₂/gNH₄-EU-1/3 449 0.19

The NH₄-EU-1/3 zeolite was mixed with SB3 type alumina from Condéa. Themixed paste was extruded through a 1.4 mm die. The extrudates were thendry impregnated with a solution of a mixture of ammonium heptamolybdate,nickel nitrate and orthophosphoric acid, and finally calcined in air at550° C., in-situ in the reactor. The amounts by weight of active oxideswere as follows (with respect to catalyst C3 thus prepared):

5.2% by weight of phosphorous oxide P₂O₅

15.2% by weight of molybdenum oxide MoO₃;

2.8% by weight of nickel oxide NiO.

The amount of EU-1/3 zeolite in the whole of catalyst C3 was 70%.

Example 4 Preparation of Catalyst C4 in Accordance with the Invention

The starting material was an EU-1 zeolite prepared in accordance withExample 1 of EP-B1-0 042 226 with a global Si/Al atomic ratio of 17.5,and an Na/Al atomic ratio of 0.8.

This EU-1 zeolite first underwent dry calcining at 550° C. in a streamof dry air for 18 hours. The solid obtained underwent three ion exchangesteps in a solution of 10 N NH₄NO₃ at about 100° C. for 4 hours for eachexchange step. The solid obtained then underwent two successivetreatments using 13 N nitric acid solutions with a volume ratio ofnitric acid solution/zeolite mass of 10 ml/g, under reflux for 4 hours.The solid obtained was designated as NH₄-EU-1/4 and had an Si/Al ratioof 59.7 and an Na/Al ratio of 0.002. The remaining physico-chemicalcharacteristics are shown in Table 4.

TABLE 4 Adsorption S_(BET) V(P/P₀ = 0.19) Sample (m²/g) ml liquid N₂/gNH-EU-1/4 409 0.16

The EU-1 crystallites were in the form of crystals 0.6 μm to 3 μm insize.

The NH₄-EU-1/4 zeolite was mixed with SB3 type alumina from Condéa. Themixed paste was extruded through a 1.4 mm die. The extrudates were thencalcined at 500° C. for 2 hours in air then dry impregnated with asolution of platinum tetramine chloride [Pt(NH₃)₄]Cl₂, and finallycalcined in air at 550° C. The platinum content in the final catalyst C4was 0.7% by weight and the zeolite content, expressed with respect tothe ensemble of the catalyst mass, was 80% by weight.

Example 5 Evaluation of Catalysts C1, C2 and C4 on a HydrocrackingResidue

Catalysts C1, C2 and C4 were evaluated by treating a hydrocrackingresidue from a vacuum distillate.

The feed had the following characteristics:

Sulphur content (ppm by weight) 13 Nitrogen content (ppm by weight) 2Pour point (° C.) +36 Initial boiling point 292 10% 343 50% 425 90% 475End point 536

Catalysts C1 and C2 prepared as described above in Examples 1 and 2 wereused to prepare a base stock from the feed described above.

The catalyst had been reduced, in situ in the reactor, in hydrogen at450° C. before the catalytic test. This reduction was carried out instages. It consisted of a stage at 150° C. for 2 hours, then an increaseof the temperature to 450° C. at a rate of 1° C./min, then a stage of 2hours at 450° C. During this reduction procedure, the hydrogen flow ratewas 1000 liters of H₂ per liter of catalyst.

The reaction took place at 315° C. at a total pressure of 12 MPa, anhourly space velocity of 2 h⁻¹ end at a hydrogen flow rate of 1000liters of H₂ per liter of feed. Under these operating conditions, thenet conversion of 400° compounds (with a boiling point of less than 400°C.) was 25% by weight and the base stock yield was about 75% by weight.

The characteristics of the oil obtained are shown in the followingtable.

Catalyst C1 Catalyst C2 Catalyst C4 Viscosity index VI 125 120 120 Pourpoint −14 −17 −20 Oil yield (wt %) 73 75 77

These examples show the importance of the process of the invention whichcan reduce the pour point of the initial feed, in the cast of ahydrocracking residue, while retaining a high viscosity (VI).

Example 6 Evaluation of Catalyst C3

Catalyst C3 prepared as in Example 3 was evaluated forhydroisomerisation of a hydrocracking residue from a vacuum distillate.

The feed had the following characteristics:

Sulphur content (ppm by weight) 105 Nitrogen content (ppm by weight) 15Pour point (° C.) +41 Initial boiling point 365  5% 428 10% 438 50% 48190% 495 95% 532 End point 536

The catalytic test unit comprised a fixed bed reactor in upflow feedmode into which 80 ml of catalyst was introduced. Each catalyst wassulphurated using a n-hexane/DMDS+aniline mixture up to 350° C. Thetotal pressure was 12 MPa, the hydrogen flow rate was 1000 liters ofhydrogen gas per liter of injected feed, and the hourly space velocitywas 1.0 h⁻¹.

The reaction took place at 330° C. at a total pressure of 12 MPa, anhourly space velocity of 1.1 h⁻¹ and at a hydrogen flow rate of 1000liters of H₂ per liter of feed.

The characteristics of the oil obtained after hydroisomerisation areshown in the following table

Viscosity index VI 118 Pour point (° C.) −19 Oil/feed yield (wt %) 78

This example shows the importance of using the catalyst of the inventionwhich can reduce the pour point of the initial feed, in the case of ahydrocracking residue, while retaining a high viscosity index (VI).

What is claimed is:
 1. A process for improving the pour point of a feedcomprising paraffins containing more than 10 carbon atoms, in whichprocess the feed to be treated is brought into contact with a catalystbased on EU-1 zeolite, at least partially in its acid form, and at leastone hydro-dehydrogenating element, at a temperature of 170° C. to 500°C., a pressure of 1 to 250 bar and at an hourly space velocity of 0.05to 100 h⁻¹, the presence of hydrogen in a proportion of 50 to 2000 l/lof feed.
 2. A process according to claim 1, in which thehydro-dehydrogenating element is a noble group VIII element.
 3. Aprocess according to claim 1, in which the hydro-dehydrogenating elementis a combination of at least one group IV metal or compound and at leastone non noble group VIII metal or compound.
 4. A process according toclaim 3, in which the catalyst contains phosphorous.
 5. A processaccording to claim 1, in which the catalyst contains a matrix and 0.5%to 99.9% by weight of EU-1 zeolite with respect to the matrix+zeolitemixture.
 6. A process according to claim 1, in which the initial boilingpoint of the feed is over 175° C.
 7. A process according to claim 1, inwhich the initial boiling point of the feed is over 280° C.
 8. A processaccording to claim 1, in which the initial boiling point of the feed isover 380° C.
 9. A process according to claim 1, in which the feedcomprises paraffins containing 15 to 50 carbon atoms.
 10. A processaccording to claim 1, in which the feed contains paraffins containing 15to 40 carbon atoms.
 11. A process according to claim 1, in which thefeed to be treated is a hydrocarbon feed selected from the groupconsisting of middle distillates, gas oils, vacuum residues,hydrocracking residues, paraffins from the Fischer-Tropsch process,synthesized oils, gas oil cuts and FCC middle distillates, oils, andpolyalphaolefins.
 12. A process for improving the pour point of a feedcomprising paraffins containing more than 10 carbon atoms, comprisingcontacting the feed with a catalyst based on EU-1 zeolite, at leastpartially in its acid form, and at least one hydro-dehydrogenatingclement, wherein the EU-1 zeolite comprises silicon and an element Twhich is Al, Fe, Ga, or B, produced by a process in which at least aportion of elements T are removed from a starting zeolite, whereby themodified zeolite has a global atomic ratio Si/T higher than that of thestarting zeolite, by at least 10% of the Si/T ratio of the startingzeolite.
 13. A process according to claim 12, in which Si/T of themodified zeolite is at least
 20. 14. A process according to claim 12, inwhich Si/T of the modified zeolite is over
 60. 15. A process accordingto claim 12, in which Si/T of the modified zeolite is at most
 600. 16. Aprocess according to claim 12, in which Si/T of the modified zeolite isat most
 300. 17. A process according to claim 12, in which T is aluminum(Al).
 18. A process according to claim 12, wherein the zeolite isobtained using at least one heat treatment of the starting zeolitefollowed by at least one treatment with a solution of an acid.
 19. Aprocess according to claim 12, in which the EU-1 zeolite is obtained bydealuminating by at least one heat treatment followed by at least onetreatment using a chemical dealuminating compound which is ammoniumhexafluorosilicate, silicon tetrachloride, orethylenediaminetetra-acetic acid, optionally in its sodium or disodiumform.
 20. A process according to claim 12, in which the EU-1 zeolite isobtained by dealuminating by at least one treatment with a chemicaldealuminating compound which is ammonium hexafluorosilicate, silicontetrachloride, or ethylenediaminetetra-acetic acid, optionally in itssodium and disodium form.
 21. A process according to claim 12, whereinthe catalyst comprises at least one matrix and 0.5% to 99.5% by weightof EU-1 zeolite with respect to the matrix+zeolite mixture.
 22. Aprocess according to claim 12, in which the hydro-dehydrogenatingelement is niobium and/or rhenium.
 23. A process for improving the pourpoint of a feed comprising paraffins containing more than 10 carbonatoms, in which process the feed to be treated is brought into contactwith a catalyst based on EU-1 zeolite, at least partially in its acidform, and at least one hydro-dehydrogenating element, at a temperatureof 170° C. to 500° C., a pressure of 1 to 250 bar and at an hourly spacevelocity of 0.05 to 100 h⁻¹, the presence of hydrogen in a proportion of50 to 2000 l/l of feed and wherein the EU-1 zeolite is produced with atleast one alkylated derivative of a polymethylene α-ω-diamine having theformula

or an amine degradation product thereon, wherein n is 3 to 12 and R₁ toR₆ are each independently alkyl or hydroxyalkyl groups, containing from1 to 8 carbon atoms and up to five of the groups R₁-R₆ can be hydrogen.24. A process according to claim 23, wherein the EU-1 zeolite isobtained by synthesis using at least one solution of an acid.
 25. Aprocess according to claim 23, wherein the polymethylene α-ω diamine isan alkylated hexamethylene diamine.
 26. A process according to claim 25,wherein the polymethylene α-ω diamine is hexamethonium salt.
 27. Aprocess for improving the pour point of a feed comprising paraffinscontaining more than 10 carbon atoms, in which process the feed to betreated is brought into contact with a catalyst based on EU-1 zeolite,at least partially in its acid form, and at least onehydro-dehydrogenating element, wherein the EU-1 zeolite comprisessilicon and an element T which is Al, Fe, Ga, or B, produced by aprocess in which at least a portion of elements T are removed from astarting zeolite, whereby the modified zeolite has a global atomic ratioSi/T higher than that of the starting zeolite, by at least 10% of theSi/T ratio of the starting zeolite and wherein the EU-1 zeolite isproduced with at least one alkylated derivative of a polymethyleneα-ω-diamine having the formula

of an amine degradation product thereon, wherein n is 3 to 12 and R₁ toR₆ are each independently alkyl or hydroxyalkyl groups, containing from1 to 8 carbon atoms and up to five of the groups R₁-R₆ can be hydrogen.28. A process according to claim 27, wherein the polymethylene α-ωdiamine is an alkylated hexamethylene diamine.
 29. A process accordingto claim 28, wherein the polymethylene α-ω diamine is hexamethoniumsalt.